<?php

/**
 * @file
 * Demonstrate validation of a textfield using AHAH.
 * This approach allows 'live' validation of a field which degrades gracefully
 * when JavaScript is not available.
 */
function ahah_example_simple_validation(&$form_state) {

    // Wrap the dynamic element in a fieldset, as some themes render the throbber
    // wrong and things appear to jump around on the screen. This can also be
    // fixed with some CSS.
    $form['wrapper_fieldset'] = array(
        '#type' => 'fieldset',
    );
    $form['wrapper_fieldset']['two_words_required'] = array(
        '#title' => t('At least two words are required in this textfield'),
        '#type' => 'textfield',
        '#default_value' => !empty($form_state['values']['two_words_required']) ? $form_state['values']['two_words_required'] : '',
        '#ahah' => array(
            'path' => 'examples/ahah_example/simple_validation/callback',
            'wrapper' => 'two_words_required_wrapper',
        ),
        '#prefix' => '<div id="two_words_required_wrapper">',
        '#suffix' => '</div>',
    );

    $form['submit'] = array(
        '#type' => 'submit',
        '#value' => t('Click Me'),
    );

    return $form;
}

/**
 * Validation function for the form. Requires that two words be entered.
 */
function ahah_example_simple_validation_validate(&$form, &$form_state) {
    $words = explode(' ', $form_state['values']['two_words_required']);
    if (count($words) < 2) {
        form_set_error('two_words_required', t('You have to enter at least two words'));
    }
}

/**
 * Submit handler for autocheckboxes.
 * Gets called even when our select is active, so we use the
 * $form_state to determine whether the submit handler should actually do
 * anything.
 */
function ahah_example_simple_validation_submit($form, &$form_state) {
    if (!empty($form_state['ahah_submission'])) {
        return;
    }

    // Continue to handle submit processing.
}

/**
 * Callback for autocheckboxes. Process the form with the number of checkboxes
 * we want to provide.
 */
function ahah_example_simple_validation_callback() {
    $form = ahah_example_callback_helper();

    // This section prepares the actual output that will be returned to the
    // browser.
    $selected_portion = $form['wrapper_fieldset']['two_words_required'];

    // To avoid doubling-up the wrapper, we have to remove it here.
    unset($selected_portion['#prefix'], $selected_portion['#suffix']);

    // Now render and output.
    $output = drupal_render($selected_portion);

    // Include (optionally) the results of any drupal_set_message() calls that
    // may have occurred.
    $output .= theme('status_messages');

    // Output the results and exit.
    drupal_json(array('status' => TRUE, 'data' => $output));
    exit();
}